How much do temperature changes affect tunes?

[EvanStang]

I am curious. If you have your car dyno tuned on an 80 degree summer day, will the tune adjust when fall hits and the average temp's are quite a bit lower? Am I right to think that cooler air would want to lean out a tune? Does the computer compensate for lower air temps and adjust the A/F accordingly? I know my car likes cooler weather.

Any input is appreciated... Thanks

 

[SteelersVenom06]

Good question. I always wondered this myself.

 

[FleeMan]

No the tune will not adjust itself. Cooler air will lean out the tune, but depending on how hot it was when you got tuned, compared to as how cold it is in the winter. Is the difference of how rich or lean it will get.

 

[MalcolmV8]

No the tune will not adjust itself. Cooler air will lean out the tune, but depending on how hot it was when you got tuned, compared to as how cold it is in the winter. Is the difference of how rich or lean it will get.

Are you talking about WOT only?

 

[FleeMan]

Are you talking about WOT only?

Yes, sorry. Shouldve been more clear on that.

 

[terminated99]

my old tune was able to adjust with colder weather it was something my tunner did so it could learn and adjust it was a sct dyno tune.

 

[04CobraMatt]

No the tune will not adjust itself. Cooler air will lean out the tune, but depending on how hot it was when you got tuned, compared to as how cold it is in the winter. Is the difference of how rich or lean it will get.

Thats wrong


The MAF is actually an amazing peice, it can detect cooler denser air and read a higher MAF Count accordingly. If the MAF Transfer function is tuned properly the computer will use more fuel to maintain the same commanded a/f ratio. This is why people wont peg thier sensor on a hot summer day but can on those cold winter days.

During hot summer days your ITA2's will never fall below 100*. Anything over 100* and your PCM is pulling timing to prevent detonation (the only way it can protect itself since these cars dont have knock sensors). On those cold nights your ITA2's will fall below 100* and your engine finally get the MAX commanded timing your tuner setup for you. So, Full timing plus cold dense air = more power.

So, bottom line is the big difference between our cars and most other cars is the Knock Sensors. Other cars wont pull timing (even FI ones) until the knock sensors go off. Ours are always pulling timing unless its really cold outside.

 

[FleeMan]

Thank you then. I stand corrected.

 

[SicStang03]

Thats wrong


The MAF is actually an amazing peice, it can detect cooler denser air and read a higher MAF Count accordingly. If the MAF Transfer function is tuned properly the computer will use more fuel to maintain the same commanded a/f ratio. This is why people wont peg thier sensor on a hot summer day but can on those cold winter days.

During hot summer days your ITA2's will never fall below 100*. Anything over 100* and your PCM is pulling timing to prevent detonation (the only way it can protect itself since these cars dont have knock sensors). On those cold nights your ITA2's will fall below 100* and your engine finally get the MAX commanded timing your tuner setup for you. So, Full timing plus cold dense air = more power.


So, bottom line is the big difference between our cars and most other cars is the Knock Sensors. Other cars wont pull timing (even FI ones) until the knock sensors go off. Ours are always pulling timing unless its really cold outside.

Doesn't race gas allow your timing to stay maxed to your tune at WOT??

 

[04CobraMatt]

Doesn't race gas allow your timing to stay maxed to your tune at WOT??

The car has no way to detect octane AFAIK. When you run race gas you usualy re-flash the PCM with a tune thats commanding ALOT more timing. the tuner can also raise the 100* to a much higher degree because he knows the engine his running a much higher octane.

For example, iv'e raised it in my tune. My PCM will only start to pull timing @ 110*, but by 130-140 its pulling as much as the stock tune. I did this because i know the MAX timing im commanding is only 21* anyway and I always run 94oct fuel.

 

[01cobravortech]

I'm tired of people posting this BS about cooler air leaning out A/F. If you have enough MAF then this is not going to happen.